Stringer Forming Apparatus and Method
Composite laminate stiffeners such as stringers are punch formed between first and second universal dies respectively carried on first and second trays. The second tray is mounted for sliding movement relative to the first tray between a punch position and a compaction position. Parts of the first and second dies are easily reconfigurable, allowing different shapes of stiffeners to be formed on the same forming apparatus.
The present disclosure generally relates to forming stringers such as those used to stiffen aircraft structures, and deals more particularly with a stringer forming apparatus and method.
2. BACKGROUNDComposite stringers such as those used in the aircraft and marine industries can be made by compression forming a flat stack of composite plies between a pair of tool dies placed in a press or similar device that compresses the dies together. Each of the dies has unique tool surfaces that are configured to produce a particular cross-sectional stringer shape. Each stringer shape therefore requires the use of dies that are unique to that shape, and cannot be used to make stringers having other shapes. The dies can be costly to manufacture, consequently, considerable expense is incurred where different sets of dies are required to produce different stringer shapes.
Producing stringers having different shapes can also be costly due to the time and labor required to change out the dies in a press. In some types of stringers, it is necessary to change parts of a die that are unique to a certain processing stage, such as compaction of parts of the stringer after it has been formed to shape. The need for changing out parts of a die further adds to the expense of the stringer manufacturing process.
Accordingly, it would be desirable to provide a stringer forming apparatus and related method that reduces the need for uniquely configured dies and die parts needed to make different stringer shapes. It would also be desirable to reduce the time and labor required to modify a forming apparatus to produce different forms of stringers.
SUMMARYThe disclosure relates in general to equipment and processes for making composite laminate parts, and more specifically to an apparatus and method of making composite laminate stringers having various shapes.
According to one aspect, a reconfigurable pallet is provided for forming composite stringers having different shapes. The pallet includes upper and lower supports that are configured to move toward and away from each other. The pallet also includes an upper die including a punch. The upper die is releasably mounted on the upper support and is configured to allow the upper die to be replaced with a different upper die. The pallet further includes a lower die mounted on the lower support. The lower die includes die block assemblies forming a die cavity into which a composite charge may be formed by the punch.
According to another aspect, apparatus is provided for punch forming a composite charge into a stringer. The apparatus includes a set of upper arms and a set of lower arms. The apparatus also includes an upper tray coupled with the upper arms. The upper tray includes a top plate and a punch. The apparatus includes a lower tray including a die having a die cavity into which the punch may form the composite charge into a stringer shape. The apparatus further includes a slide assembly mounting the lower tray on the lower arms for sliding movement between a first position in which the punch forms the composite charge into the die cavity, and a second position in which the top plate is used to compact the composite charge.
According to still another aspect, a method is provided of forming a composite stringer. The method includes placing a flat composite charge between a first die and a second die, and moving the second die to a punch forming position aligned with the first die. The method also includes a punch for forming the flat composite charge into the shape of a stringer while the second die is in the punch forming position. The method includes shifting the second die from the punch forming position to a compaction position, and compacting at least a portion of the stringer using the first die while the second die is in the compaction position.
One of the advantages of the disclosed apparatus method is that the time and labor needed to compression form composite stringers can be reduced. Another advantage is that universal dies are provided that can easily and quickly reconfigured to produce stringers having different cross sectional shapes. A further advantage is that the die changing process is partially automated, thereby reducing labor costs and increasing throughput
The features, functions, and advantages can be achieved independently in various examples of the present disclosure or may be combined in yet other examples in which further details can be seen with reference to the following description and drawings.
The novel features believed characteristic of the illustrative examples are set forth in the appended claims. The illustrative examples, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative examples of the present disclosure when read in conjunction with the accompanying drawings, wherein:
The disclosed embodiments relate to a method and apparatus for making composite stiffeners such as stringers used in the aircraft, marine and other industries. For example, referring to
Depending upon the application, the stringers 44 may have various out-of-plane features such as contours, pad ups and/or joggles (not shown) at one or more locations along their lengths. Contouring of the stringers 44 is sometimes necessary in order to match the contour of a skin 35 to which the stringers 44 are attached. For example, as shown in
Attention is now directed to
In use, with the upper die 55 in a raised position above the lower die 57, a flat, multiply ply composite charge 64 is placed between the upper die 55 and upper surfaces of the die blocks 60. The top plate 56 is then displaced downwardly with a force F, causing the punch 62 to compression form or “punch” the charge 64 into the die cavity 70, thereby forming a pair of web portions 68. As web portions 68 of the stringer 44 are being formed by the punch 62, flange portions 66 of the stringer 44 are constrained but are allowed to slide between the top plate 56 and the die blocks 60.
Next, as shown in
Attention is now directed to
The forming apparatus 76 further comprises an upper tray 84 having an upper die 55, and a lower tray 86 having a lower die 57. The upper tray 84 is connected to the upper arm 78 by a plurality of upper pivots 88 which allow the upper tray 84 to bend as required in the XZ plane (
The upper tray 84 further includes inflatable clamping hoses 102 that apply pressure to the composite charge 64 through a pair of laterally spaced caul plates 63 positioned on opposite sides of the punch 62. The caul plates 63 function to evenly apply clamping pressure to the composite charge 64, and also act as a heat sink to evenly distribute heat applied to the composite charge 64 by heating blankets 65 interposed between the caul plates and the hoses 104. Referring to
The lower tray 86 is pivotally connected to the lower arms 80 by a plurality of lower pivots 90. The lower tray 86 is releasably connected to adapter arms 108 by removable pivot pins 91. The lower tray 86 comprises die block assemblies 71 that are reconfigurable to allow different stringer shapes to be formed. The die block assemblies 71 include a plurality of die blocks 60 slidably mounted on a flexible bottom plate 58. The die block assemblies 71 further comprise a cap assembly 72 which includes die block adapters 98 that cover and are removably mounted on the die blocks 60. The die block adapters 92 have tool surfaces that determine in part, the cross-sectional shape of the stringer 44 being formed. In some applications, depending on the shape of the stringer being formed, it may be desirable to clamp portions of the composite charge, such as the flanges, to the die block adapters 92. Accordingly, the lower die 57 may optionally include a vacuum clamping capability in which the top of each of the die block adapters 92 is provided with one or more air inlet openings 119 that are connected with vacuum ports 121 on the side. The vacuum ports 121 are connected through hoses (not shown) to a vacuum source 125 (
The die blocks 60 include oval shaped cooling passageways 93 which allowing cooling of the die block assemblies 71 either by convection or forced air. The die blocks 60 may be constrained together using rods or cables (both not shown) which pass through circular holes 75 in the die blocks. The circular holes 75 may function to dissipate heat from the die blocks 60. An inflatable block separation hose 107 is positioned between the die blocks 60 and acts as a barrier or stop that maintains a minimum separation distance between the die blocks 60, thus preventing the punch 62 from unintentionally coming into contact with the tops of the die block adapters 92 when upper die 55 is lowered toward the lower die 57 during a forming operation.
Referring to
Attention is now directed to
The bottom adapter bases 116 are mounted on linear guides 99 that slide along tray rails 97 on the lower arms 80. The linear guides 99 and tray rails 97 form a slide assembly that allow the lower tray 86 to move along the Y axis between two operating positions discussed below. Referring also to
As discussed above, the lower tray 86 can be shifted by the motor drives 100 linearly along the lower arms 80.
Referring to
Various control systems can be used to control operation of the forming apparatus 76. For example, referring to
Referring now to
Continued downward movement of the upper arms 78 causes the punch 62 to form the composite charge 64 into the die cavity 70, while the flange portions 66 of the charge 64, although restrained, are allowed to slip between the caul plates 63 and the top of the die block adapters 92. The pressure in the hoses 104 is gradually reduced as the punch 62 moves down, permitting the die blocks 60 to move apart as the punch 62 forms the composite charge 64 into the die cavity 70.
Next, the upper arms 78 are displaced upwardly, causing the punch 62 to be withdrawn from the die cavity 70. Then, the motor drives 101 are activated, causing the entire lower tray 86 to move along the Y axis from the punch position 87 shown in
Attention is now directed to
Examples of the disclosure may find use in a variety of potential applications, particularly in the transportation industry, including for example, aerospace, marine, and other application where composite stiffeners such as composite laminate stringers for aircraft, may be used. Thus, referring now to
Each of the processes of method 152 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
As shown in
Systems and methods embodied herein may be employed during any one or more of the stages of the aircraft manufacturing and service method 152. For example, components or subassemblies corresponding to production process 160 may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft 154 is in service. Also, one or more apparatus examples, method examples, or a combination thereof may be utilized during the production processes 160 and 162, for example, by substantially expediting assembly of or reducing the cost of an aircraft 154. Similarly, one or more of apparatus examples, method examples, or a combination thereof may be utilized while the aircraft 154 is in service, for example and without limitation, to maintenance and service 168.
As used herein, the phrase “at least one of”, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of each item in the list may be needed. For example, “at least one of item A, item B, and item C” may include, without limitation, item A, item A and item B, or item B. This example also may include item A, item B, and item C or item B and item C. The item may be a particular object, thing, or a category. In other words, at least one of means any combination items and number of items may be used from the list but not all of the items in the list are required.
The description of the different illustrative examples has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the examples in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative examples may provide different advantages as compared to other illustrative examples. The example or examples selected are chosen and described in order to best explain the principles of the examples, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various examples with various modifications as are suited to the particular use contemplated.
Claims
1. A reconfigurable pallet for forming composite stringers having different shapes, comprising:
- an upper support;
- an upper die including a punch, the upper die being releasably mounted on the upper support and configured to allow the upper die to be replaced with a different upper die;
- a lower support, the upper and lower supports being configured to move toward and away from each other; and
- a lower die mounted on the lower support, the lower die including die block assemblies forming a die cavity into which a composite charge may be formed by the punch.
2. The reconfigurable pallet of claim 1, wherein:
- the upper support includes upper arms,
- the die block assemblies are reconfigurable to allow different stringer shapes to be formed, and
- the upper die includes an upper tray having a top plate, wherein the punch is mounted on the top plate.
3. The reconfigurable pallet of claim 2, further comprising:
- upper pivots pivotally mounting the top plate on the upper arms, the upper pivots including removable pivot pins allowing the top plate to be removed from the upper arms.
4. The reconfigurable pallet of claim 2, further comprising:
- slideable connections mounting the upper tray for sliding movement on the upper arms and configured to allow the upper tray to be released from the upper arms and replaced by a differently configured upper tray.
5. The reconfigurable pallet of claim 1, wherein:
- the lower support includes lower arms, and
- the lower die includes a lower tray having the die block assemblies mounted thereon.
6. The reconfigurable pallet of claim 5, further comprising:
- lower pivots pivotally mounting the lower tray on the lower arms.
7. The reconfigurable pallet of claim 5, wherein the lower tray is slideably mounted on the lower arms for movement between a stringer forming position and a stringer compaction position.
8. The reconfigurable pallet of claim 7, further comprising:
- motor drives carried on the lower arms and configured to drive the lower tray along the lower arms between the stringer forming position and the stringer compaction position.
9. The reconfigurable pallet of claim 1, wherein the die block assemblies include:
- die blocks shiftable toward and away from each other, and
- die block adapters removably mounted on the die blocks and configured to allow the lower die to be reconfigured to form stringers having different shapes.
10. Apparatus for punch forming a composite charge into a stringer, comprising:
- a set of upper arms;
- an upper tray coupled with the upper arms, the upper tray including a top plate and a punch;
- a set of lower arms;
- a lower tray including a die having a die cavity into which the punch may form the composite charge into a stringer shape; and
- a slide assembly mounting the lower tray on the lower arms for sliding movement between a first position in which the punch forms the composite charge into the die cavity and second position in which the top plate compacts the composite charge.
11. The apparatus of claim 10, wherein the slide assembly includes:
- rails respectively extending along the lower arms, and linear guides respectively mounted for movement along the rails and coupled with the lower tray.
12. The apparatus of claim 10, further comprising:
- pivots connecting the upper tray with the upper arms and configured to allow the upper tray to pivot relative to the upper arms.
13. The apparatus of claim 10, further comprising:
- pivots connecting the lower tray with the lower arms and configured to allow the lower tray to pivot relative to the lower arms.
14. The apparatus of claim 10, wherein the upper tray includes:
- a first section having the punch mounted thereon, and
- a second section adjacent to and spaced from the first section configured to engage and compact a portion of the stringer.
15. The apparatus of claim 10, wherein the lower die includes:
- a plate,
- die blocks mounted on the plate, and
- die block adapters on the die blocks having tool surfaces for forming the composite charge within the die cavity, the die block adapters being configured to be removable and replaced by any of a plurality of die block adapters having differently configured tool surfaces.
16. A method of forming a composite stringer, comprising:
- placing a flat composite charge between a first die and a second die;
- moving the second die to a punch forming position in an alignment with the first die;
- punch forming the flat composite charge into a shape of a stringer while the second die is in the punch forming position, including forcing the flat composite charge into a die cavity in the second die using a punch on the first die;
- shifting the second die from the punch forming position to a compaction position; and
- compacting at least a portion of the stringer using the first die while the second die is in the compaction position.
17. The method of claim 16, wherein shifting the second die includes moving the second die laterally out of an alignment with the first die.
18. The method of claim 17, wherein moving the second die includes sliding the second die along rails using a motor drive.
19. The method of claim 16, further comprising:
- releasably mounting the first die on a support;
- releasing and removing the first die from the support; and
- replacing the first die with a third die, including releasably mounting the third die on the support.
20. The method of claim 16, further comprising:
- contouring the first die and the second die by pivoting the first die and the second die.
Type: Application
Filed: Mar 7, 2022
Publication Date: Sep 7, 2023
Inventors: Lisa Christina Carlson (Auburn, WA), Silas Lawton Studley (Seattle, WA), Daniel Saeil Martin (Stanwood, WA), Kurtis Shuldberg Willden (Kent, WA), Gagandeep Saini (Snohomish, WA), Steven Joseph Plummer (Seattle, WA)
Application Number: 17/653,758